node: Fix undefined senders in notifications test.
node: Fix undefined senders in notifications test.

zulip/zulip,showell/zulip,rht/zulip,andersk/zulip,hackerkid/zulip,brainwane/zulip,kou/zulip,rishig/zulip,showell/zulip,rishig/zulip,shubhamdhama/zulip,zulip/zulip,zulip/zulip,hackerkid/zulip,tommyip/zulip,synicalsyntax/zulip,brainwane/zulip,rishig/zulip,shubhamdhama/zulip,rht/zulip,eeshangarg/zulip,zulip/zulip,kou/zulip,kou/zulip,synicalsyntax/zulip,dhcrzf/zulip,hackerkid/zulip,showell/zulip,punchagan/zulip,punchagan/zulip,dhcrzf/zulip,rht/zulip,kou/zulip,andersk/zulip,tommyip/zulip,dhcrzf/zulip,timabbott/zulip,brainwane/zulip,timabbott/zulip,andersk/zulip,andersk/zulip,tommyip/zulip,showell/zulip,timabbott/zulip,shubhamdhama/zulip,rht/zulip,synicalsyntax/zulip,brainwane/zulip,andersk/zulip,brainwane/zulip,hackerkid/zulip,eeshangarg/zulip,timabbott/zulip,punchagan/zulip,punchagan/zulip,tommyip/zulip,rishig/zulip,tommyip/zulip,kou/zulip,rishig/zulip,showell/zulip,punchagan/zulip,rishig/zulip,rht/zulip,dhcrzf/zulip,kou/zulip,synicalsyntax/zulip,dhcrzf/zulip,brainwane/zulip,tommyip/zulip,showell/zulip,shubhamdhama/zulip,eeshangarg/zulip,zulip/zulip,zulip/zulip,andersk/zulip,hackerkid/zulip,zulip/zulip,shubhamdhama/zulip,shubhamdhama/zulip,tommyip/zulip,synicalsyntax/zulip,shubhamdhama/zulip,rishig/zulip,dhcrzf/zulip,dhcrzf/zulip,hackerkid/zulip,eeshangarg/zulip,brainwane/zulip,hackerkid/zulip,eeshangarg/zulip,rht/zulip,timabbott/zulip,showell/zulip,timabbott/zulip,synicalsyntax/zulip,andersk/zulip,punchagan/zulip,eeshangarg/zulip,rht/zulip,timabbott/zulip,eeshangarg/zulip,synicalsyntax/zulip,kou/zulip,punchagan/zulip